Thermoelectric retrofit unit for a liquid recipient

ABSTRACT

A retrofit unit for heating and cooling liquid stored in a recipient, the retrofit unit comprising: a housing defining a cavity and allowing the retrofit unit to be external to the recipient; a thermoelectric device in the cavity, comprising at least one thermoelectric module having a heat radiation side and a heat absorption side; a control unit in the cavity, for controlling the energy to be applied to the thermoelectric module; and a connecting element on the housing, the connecting element allowing the thermoelectric device one of direct contact and indirect contact with the liquid stored in the recipient to selectively heat and cool the liquid by emitting and absorbing heat, respectively.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 USC§119(e) ofProvisional Patent Application bearing Ser. No. 61/036,107 entitled“Thermoelectric retrofit unit for hot water heater”, filed Mar. 13,2008, the contents of which are hereby incorporated by reference.

TECHNICAL FIELD

The present patent application relates to the field of heating andcooling a liquid contained in a recipient, such as a water tank, aswimming pool, and others.

BACKGROUND

Recent studies have shown that residential hot water heating canrepresent as much as 30% of the overall electrical consumption in anaverage household. As energy demand and cost continue to grow there isan ever increasing need for more efficient means of heating water.

Also associated to the ever increasing demand for electrical energy isthe problem of higher and longer peak demand periods. Energy providershave begun to create what are called demand side management programs.These programs have been created with the ultimate goal of lowering peakand overall energy consumption. Primarily, energy providers, throughincentives, encourage, and in some cases require, their customers toadopt more energy efficient technologies.

With respect to hot water heaters, there simply aren't any availabletechnologies that can address both the need for overall and peak demandreduction. The only solutions brought on by the energy providers arecontrol solutions geared towards the reduction of peak electrical demandduring these peak periods. A typical control program involvescontrolling the times at which a customer's hot water heater has accessto electrical energy. This is done in several ways. Either through adedicated electrical meter which can be remotely controlled by theprovider or with the use of a dedicated timer that simply cuts power tothe hot water heater during known peak demand periods. Because there isa risk that a customer could run out of hot water, adding hot watercapacity is required. Adding an additional tank or replacing theexisting tank with a larger sized unit is part of the overall strategy.While this type of program reduces the overall peaks, it inherently willcause a more significant problem upon mass adoption. Under theseprograms the customer is required to significantly increase the overallhot water capacity, thus increasing his overall electrical energyconsumption, and will also increase the standby loss associated withconventional hot water heater tanks.

Furthermore, in a conventional electric hot water heater tank, there isprovided at least one electrical heating element. These heating elementsare known to have an operational efficiency that is less than 100%. Withelectrical resistive heating elements, the resistive or “Joule heat”created is proportional to the square of the current applied (I²R).This, coupled with the fact that conventional hot water tanks constantlylose heat and thus have a standby loss (average energy consumption usedfor maintaining set temperature throughout the tank for a 24 hr period)of 89 to 95 watts/hour, results in less than 100% efficiency.Conventional hot water heaters simply cannot operate at greater than 95%efficiency.

Therefore, there is a need for a system that will overcome some of thedrawbacks of the prior art.

SUMMARY

The system and methods described herein address these needs as well asothers by using thermoelectric module technology.

According to a broad aspect there is provided a retrofit unit forheating and cooling liquid stored in a recipient, the retrofit unitcomprising: a housing defining a cavity and allowing the retrofit unitto be external to the recipient; a thermoelectric device in the cavity,comprising at least one thermoelectric module having a heat radiationside and a heat absorption side; a control unit in the cavity, forcontrolling the energy to be applied to the thermoelectric module; and aconnecting element on the housing, the connecting element allowing thethermoelectric device one of direct contact and indirect contact withthe liquid stored in the recipient to selectively heat and cool theliquid by emitting and absorbing heat, respectively.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages of the present invention will becomeapparent from the following detailed description, taken in combinationwith the appended drawings, in which:

FIG. 1 is a schematic diagram of a system having a retrofit unitconnected to a recipient by a single passage, according to oneembodiment;

FIG. 2 is a side view of a system having a retrofit unit connected to arecipient by a system inlet pipe and a drain pipe, according to oneembodiment;

FIG. 3 is a side view of a system having a retrofit unit being connectedto a recipient by inlet and outlet passages, according to oneembodiment;

FIG. 4 is a cross-sectional side view of a retrofit unit of FIG. 1showing the liquid flowing in the cavity of the housing, according toone embodiment;

FIG. 5 is a cross-sectional side view of a retrofit unit as shown inFIG. 4 including a heat exchanger pipe system, according to oneembodiment;

FIG. 6 is a schematic illustration of a system having a retrofit unitbeing conductively connected to the surface of a recipient, according toone embodiment; and

FIG. 7 is a cross-sectional view of the a retrofit unit as shown in FIG.6, according to one embodiment.

It will be noted that throughout the appended drawings, like featuresare identified by like reference numerals.

DETAILED DESCRIPTION

Reference is now made to FIG. 1, which illustrates a cross-sectionalside view of an embodiment of a system 10 for heating or cooling liquidstored within a recipient 11 to which a thermoelectric retrofit unit 70is connected via a connecting element 91. The thermoelectric retrofitunit 70 comprises a housing 181 defining a cavity to allow thethermoelectric retrofit unit 70 to be external to the housing 181 of therecipient 11. In one embodiment the housing of the retrofit unit 70 canbe made of metal such as steel or plastic materials such aspolypropylene, polycarbonate, polyethylene, or any plastic materialswhich are capable of withstanding high operating temperatures.

In one embodiment, the connecting element 91 is located on the housing181 and comprises at least one passage for fluidly connecting theretrofit unit 70 to the recipient and allowing the liquid to flow insidea cavity of the thermoelectric retrofit unit 70. The liquid may flow inand out of the retrofit unit 70 via a single passage. In anotherembodiment, two passages are provided, allowing liquid to flow into theunit 70 via an inlet passage and out of the unit via an outlet passage.In one embodiment, the inlet passage is suitable to be connected to asource such as the city water. In one embodiment, the outlet passage issuitable to be connected to, for example, a drain of the recipient toallow the liquid to exit the retrofit unit 70 and enter the recipient.In another embodiment, the thermoelectric retrofit unit 70 mates, viathe connecting element 91, with any type of outlet/inlet found on aconventional hot water heater tank, such as a heating element bracket, adrain valve, or the like

In one embodiment, liquid from the recipient 11 may circulate inside thethermoelectric retrofit unit 70 and will come into contact with one sideof a thermoelectric device 80 to be heated or cooled during thiscirculation process. Some possibilities for the liquid include water,glycol, oil, and other liquids that need to be maintained at a specifictemperature.

The thermoelectric device 80 is inside the thermoelectric retrofit unit70 to allow the hot or cold side to come into thermal contact with theliquid in a direct or indirect manner, thereby raising or lowering thetemperature of the liquid. While FIG. 1 illustrates the thermoelectricdevice 80 as being positioned on a sidewall of the thermoelectricretrofit unit 70, other alternatives are possible which do not requirethe thermoelectric device 80 to be in contact with a sidewall or to beplaced on the far-side of the unit 70 with respect to the recipient 11.

Reference is now made to FIG. 2, which is a side view of a system 20having a thermoelectric retrofit unit 70 fluidly connected to arecipient 11. In this embodiment, the recipient 11 is a hot water tankfor heating water for residential purposes. A city water inlet 171allows water to flow into the unit 70 and the drain valve 172 flows thewater into the recipient 11. The back side of the unit 70 has a heatsink 174 along part of its lengths, and fans 175 to maintain the heatsink 174 at ambient or higher temperatures.

In one embodiment, the retrofit unit 70 has the capability of being usedin conjunction with at least one of the heating elements 12 found in therecipient. FIG. 3 illustrates a side view of a system 120 having athermoelectric retrofit unit 70 connected to the surface of a recipient11. The thermoelectric retrofit unit 70 is electrically connected to therecipient 11 via the wire 152 for the heating element of the recipient.The electrical ground point found near the heating element is also usedfor the thermoelectric retrofit unit 70. Also illustrated in theembodiment shown in FIG. 3 are the inlet passage 176 and outlet passage177, which allow the liquid to circulate in and out of the retrofit unit70, respectively.

Reference is now made to FIG. 4, which illustrates a cross-sectionalside view of another embodiment of a thermoelectric retrofit unit 70.The thermoelectric retrofit unit 70 comprises a cavity 74 which isfluidly connected to the recipient 11 and has a gasket 88 for providinga waterproof seal of the mating connection between the cavity 72 and therecipient 11. The retrofit unit 70 contains a thermoelectric device 80,which comprises at least one thermoelectric module 71.

Thermoelectric modules are solid-state devices (no moving parts) thatconvert electrical energy into a temperature gradient, known as the“Peltier effect” or convert thermal energy from a temperature gradientinto electrical energy, the “Seebeck effect”. When the appropriate poweris applied, from a battery or other DC source, one side of the modulewill be made cold while the other is made hot. If the polarity orcurrent flow through the module is reversed, the cold side will becomethe hot side and vice versa. This allows thermoelectric modules to beused for heating, cooling and temperature stabilization. Sincethermoelectric modules are electrical in nature, in a closed-loop systemwith an appropriate temperature sensor and controller, they can maintaintemperatures that vary by less than one degree Celsius.

Larger areas than an individual module can maintain are cooled or havethe temperature controlled by using multiple modules like the module 71.For example, individual thermoelectric modules having physicaldimensions of 40 mm wide by 40 mm long by 3.5 mm thick can be used.These modules operate at 24 volts DC and are electrically connected inseries in order to divide the supplied 336 DC volts into the modules. Itis important to note that a variable number of modules that operate atdifferent voltages (ex: 12 vdc or 17.4 vdc) may be included and/or used.The module will absorb heat on the “cold side” and eject it out the “hotside”.

Thermoelectric modules have advantages over conventional methods ofheating liquid, such as those that use electrical resistance heatingelements. A thermoelectric module may be used continuously for twenty ormore years and the life of a module often exceeds the life of theassociated equipment. In addition, Mean Time Between Failures (MTBFs) inexcess of 200,000 hours are not uncommon in such cases and this MTBFvalue generally is considered to be an industry standard. Athermoelectric module can be used to provide greater than 100%efficiency to the hot water heater given that when used for heating,thermoelectric modules can produce heat energy with over 200%efficiency. The heat created by a thermoelectric module is proportionalto the current because the flow of current is working in two directions(the thermoelectric effect). Therefore, the total heat ejected by thethermoelectric module is the sum of the current plus the heat beingpumped through the heat absorption side.

For example, the actual heat/wattage being created by the thermoelectricmodule may be as follows; 12 vdc×5 amps=60 watts of energy consumed+45heat absorption watts=105 watts of total heat pumped to the heatradiation side of the module while using only 60 watts of electricalenergy. This describes a thermoelectric module operating at 175%efficiency when being used for heating. The efficiency at which athermoelectric module will operate is dependent of many factors. Forexample, a factor can be the current applied to the thermoelectricmodule or can be the temperature differential between the both sides ofthe thermoelectric module. The smaller the temperature differential is,the more heat pumping power the thermoelectric module will generate andthus the more efficient it will be.

In the embodiment illustrated in FIG. 4, the thermoelectric device 80comprises two heat sinks 76, 77 connected to each side of thethermoelectric module 71. In this embodiment, the two heat sinks 76, 77and the thermoelectric module 71 form the thermoelectric device 80. Oneheat sink 76 is conductively connected to the heat radiation side of thethermoelectric module 71 to function as an element to heat or cool thewater contained within the cavity 74 and/or the recipient 11. The heatsink 77 is conductively connected to the heat absorption side of thethermoelectric module 71 to function as a tempering mechanism in orderto maintain the temperature of the heat absorbing side at roomtemperature or above, in order to keep the temperature differentialbetween the heat absorption and heat radiating sides as small aspossible. In one embodiment, there is provided a spacer 180 between thethermoelectric module 71 and the heat sink 77.

In one embodiment, a fan 79 mounted to the heat sink 77 that isconductively connected to the heat absorption side of the thermoelectricmodule 71 is used for assisting in the tempering of the heat sink 77 byblowing air towards the heat sink 77. Alternatively, the fan 79 may alsoincorporate the use of an inlet duct 81 which is positioned in such away as to retrieve warmer air from various sources, such as the airgenerally located closer to the ceiling height of a room, the air withinthe vicinity of a heat source such as an ac motor found in HVAC systems,outdoor air (if above room temperature), or heat energy escaping fromthe recipient 11 to which the retrofit unit is mated. The inlet duct 81may be used as a heat recuperating device by re-circulating heated airthat has been heated with wasted energy and using it to temper and heatthe heat sink 77 located on the heat absorption side of thethermoelectric module 70 in order to minimize the temperaturedifferential, thus maximizing the thermoelectric module's efficiency.Alternatively the use of ambient heat energy which is normally wastedand has also been created with technologies such as thermo pumps whichcan operate at greater than 400% efficiency may serve to increaseoverall energy efficiency.

In a further embodiment, the thermoelectric retrofit unit 70 may includethe use of a circulating pump 84 in order to facilitate and/oraccelerate the circulation of water between a recipient and thethermoelectric retrofit unit 70. The circulating pump also serves toprovide the capability of heating all of the liquid located throughoutthe recipient 11 and, more specifically, the water located below theheating elements, in order to increase overall hot water capacity by,for example, five to ten gallons. This may also help to maximizeoff-peak energy consumption.

The thermoelectric retrofit unit 70 comprises a control unit 75. In oneembodiment the control unit 75 can be a Control Processing Unit (CPU), aprocessor, or the like used to control the current being applied to thethermoelectric module 71. The current level applied is based on severalfactors, such as the time allotted to heat the water in order to stayout of peak periods. For example, if in a colder climate where energyconsumption peaks for longer periods of time due to heating and theallotted time for off peak operation is reduced, then the control unit75 will operate the thermoelectric module 71 at higher power in order toheat the required volume of liquid in a shorter amount of time.

With respect to predicted water consumption, the control unit 75 maycalculate this based on historical consumption data. For example, if thepredicted water consumption of the user for the next twenty-four hoursis sixty-four gallons, the system will then optimize the output wattagebeing applied to the thermoelectric module in order to heat sixty-fourgallons over the entire twenty-four hour period versus operating at itsfull power capability for a shorter amount of time. The first scenariorepresents a much higher degree of efficiency because thermoelectricmodules typically will operate more efficiently at less than fullcapacity.

In another embodiment, the control unit 75 can also take into accountambient temperatures. For example, in a warmer climate, when home ownersare away they will typically lower the air conditioning, thus increasingthe ambient temperature in the home and allowing the thermoelectricmodule to operate more efficiently. This is because by increasing theambient temperature, the home owner is thereby reducing the temperaturedifferential of the heat absorption and radiating sides of the module.The control unit 75 can then operate the thermoelectric module 70 athigher power during this more efficient operating period. It is to beunderstood that a role of the control unit 75 is to maximize operationalefficiency of the system 10 by maximizing system 10 operating timeduring the most favourable conditions.

In yet another embodiment, the control unit 75 is an intelligent controlunit used to control the supply of power to the thermoelectric module 71and the heating elements 12 on the recipient 11, record and monitortemperature readings, monitor system integrity and normal operation,manage heating or cooling cycles in such a way as to maximize theoperating time of the system in off-peak periods, and calculate andstore consumption.

In one embodiment the system may also incorporate the use of one or morethermometers 90 connected to the control unit 75, and used to monitorvarious temperature points, such as both sides of a thermoelectricmodule 71, liquid temperatures found in the thermoelectric retrofit unit70 and within the recipient 11, indoor and outdoor air temperatures, andso on.

In one embodiment, the thermoelectric retrofit unit 70 comprises a powersupply unit 82 used for providing AC and/or DC power to thethermoelectric retrofit unit 70 and/or the recipient 11. In yet anotherembodiment there is provided a means for converting the electricalsupply of energy to the thermoelectric device from Alternating Current(AC) to Direct Current (DC). This conversion is achieved using standardhigh power rectifying diodes which basically combine the AC electricalcycle into a DC electrical cycle. Another method that may be used is ahigh speed switching power supply. Other components such as filteringcapacitors may also be used to linearize the output DC current. Oneembodiment may include a fan 79 mounted to the heat sink 77 that isconductively connected to the heat absorption side of the thermoelectricmodule 71, the fan 79 assisting in the tempering of the heat sink 77.The fan 79 may also incorporate the use of an inlet duct 81 which ispositioned in a manner to retrieve warmer air from various sources suchas air generally located closer to the ceiling height of a room, airwithin the vicinity of a heat source such as an ac motor found in HVACsystems, outdoor air (if above room temperature), and heat energyescaping from the recipient to which the thermoelectric retrofit unit 70is mated. Retrieval of heated air using the inlet duct 81 is done tofurther help with the maintaining of the cavity 74 at a temperatureequal to or above the temperature of the heat sink 77 in order tofurther maximize overall system efficiency.

Also provided in one embodiment is a hot and cold water separator 185.The separator 185 provides the functionality of increasing fluiddisplacement through convection between the cavity 74 and the recipient11 by creating a thermosiphon. It can be attached to the inner walls ofthe passage of retrofit unit 70 using various means, such as a plasticbracket, positioned so as not to disrupt the flow of the liquid. Coldliquid will therefore be directed inside the retrofit unit 70 towardsthe bottom of the cavity, and the pump 84 will circulate hot liquid backout through the passage and into the recipient 11.

As illustrated in FIGS. 4 and 5, there may be a power supply unit 82used for providing AC and/or DC power to the thermoelectric retrofitunit 70 and or the hot water heater, as well as a means for convertingthe electrical supply of energy to the thermoelectric modules 71 fromAlternating Current (AC) to Direct Current (DC).

In another embodiment, there is provided a heat recuperation unit 83between the power supply 82 and the heat sink 77, which may bepositioned to recuperate the heat being dissipated by the power supplyunit 82 and then used to distribute the heat to the heat sink 77, whichis conductively connected to the heat absorption side of thethermoelectric module 71. The heat recuperation unit 83 provides thepower supply with a greater overall efficiency since during electricalconversion, energy is lost in the form of heat which is in turndissipated, thus reducing the overall efficiency of the power supplyunit 82. The industry efficiency standard for AC to DC power supplies isapproximately 80%. Recuperation of this heat generated by the powersupply serves to substantially increase the power supply unit'sefficiency.

In yet another embodiment, a heat sink 77 located on the heat absorptionside of the thermoelectric module 71 and the heat recuperation unit 83found in the power supply unit 82 are positioned in such a way as tomaintain conductive contact with each other.

In a further embodiment, there is provided a mechanism for reversing theelectrical polarity of the current supplied to the thermoelectric modulein order to switch between heating and/or cooling cycles. This is doneusing a simple dual-pull dual-throw electrical relay. As an example thiswould be done when during extended periods there is no hot water usage,such as family vacations. The standby loss of energy will besignificantly higher if the water in the recipient is kept hot ratherthen maintaining the water at cooler temperatures. The water is coolednot only to reduce energy consumption but also in order to maintain safetemperatures that are not within bacterial growth ranges. Standby energyconsumption is therefore significantly reduced and this providesbacterial growth prevention.

FIG. 5 illustrates an embodiment incorporating a hot/cold plate 85. Ahot/cold plate is a plate, made of aluminum or other materials,containing internal tubing 86 through which a liquid is forced, toabsorb heat transferred to the plate. As illustrated in FIG. 5, hot/coldplate 85 is used as a hot plate and the liquid from the recipient 11circulates in the tubing 86 of the hot plate. In another embodiment, asillustrated in FIG. 5, a circulation pump 89 is used to circulate theliquid in the hot/cold plate 85. The hot/cold plate 85 transfers theheat/cold energy to the liquid flowing through the piping 86 embeddedtherein. The liquid is heated or cooled by the plate 85 which isconductively connected to the thermoelectric module 71. The liquid thenflows back into the recipient 11 via the piping 86.

In yet another embodiment, the heat sink 77 of FIG. 5 may be substitutedby another hot/cold plate with piping embedded therein. This hot/coldplate may comprise a liquid coolant that flows in a closed circuit, andwhich is circulated by a circulating pump. The hot/cold plate wouldfunction similarly to the heat sink 77 to act as a tempering mechanismin order to maintain the temperature of the heat absorbing side at roomtemperature or above, in order to keep the temperature differentialbetween the heat absorption and heat radiating sides as small aspossible. The liquid coolant circulates between the hot/cold platesystem and a radiator, provided inside the retrofit unit 70 or externalthereto, in a closed circuit. The radiator may have a fan attachedthereto.

Reference is now made to FIG. 6, which illustrates an embodiment of asystem 10 for heating or cooling liquid stored within a recipient 11 towhich a thermoelectric retrofit unit 50 is affixed. In one embodiment,the recipient 11 can have an opened or closed housing like conventionalwater tanks. In this embodiment, the thermoelectric retrofit unit 50provides heating or cooling of stored liquid by maintaining conductivesurface contact with the recipient 11.

In FIG. 6, the hot side of the thermoelectric device 60 is provided onthe side of the housing 181 in contact with a surface of the recipient11 and heat is used to raise the temperature of the liquid inside therecipient 11 via the thermal contact between the thermoelectric device60 and the liquid in the recipient 11 when the two surfaces are incontact with each other. By reversing the polarity or current flowthrough the thermoelectric device 60, the liquid inside the recipient 11may be cooled instead of heated. In one embodiment, the contact surface13 of the thermoelectric retrofit unit 50 can be made of a material thatallows an efficient transfer of heat from the thermoelectric retrofitunit 50 to the recipient 11. In some embodiments, a connecting element(not shown) such as straps, thermally conductive adhesives, thermallyconductive epoxy compounds and/or the like can be used to apply apressure between the thermoelectric retrofit unit 50 and the recipient10 to provide stability to the system 10 and to ensure the propercontact between the two surfaces.

FIG. 7 illustrates one embodiment of the thermoelectric retrofit unit 50used for heating or cooling water, where the mating occurs conductivelyvia a surface of the recipient 11. In one embodiment, the thermoelectricretrofit unit comprises a conductive heat transferring block to improvethermal contact with one or more individual surfaces of the recipient 11in which fluid is to be heated and/or cooled. A thermoelectric module 71is placed between at least two opposing blocks. A first heattransferring block 95 is placed between the recipient 11 and the heatdissipating side of the thermoelectric module 71 in order toconductively transfer heat generated by the module to the recipient 11.A second heat sink 97 operatively connected to the heat absorption sideof the thermoelectric module functions as a tempering device in order tomaintain the temperature of the heat absorbing side at room temperatureor above in order to keep the temperature differential between the heatabsorption and heat radiating sides as small as possible. Possiblematerials for the heat transferring block 95 are aluminium, copper,gold, and any other highly thermally conductive metals or syntheticcompounds such as silicon-carbide.

The embodiments of the invention described above are intended to beexemplary only. The scope of the invention is therefore intended to belimited solely by the scope of the appended claims.

1. A retrofit unit for heating and cooling liquid stored in a recipient,the retrofit unit comprising: a housing defining a cavity and allowingthe retrofit unit to be external to the recipient; a thermoelectricdevice in the cavity, comprising at least one thermoelectric modulehaving a heat radiation side and a heat absorption side; a control unitin the cavity, for controlling the energy to be applied to thethermoelectric module; and a connecting element on the housing, theconnecting element allowing the thermoelectric device one of directcontact and indirect contact with the liquid stored in the recipient toselectively heat and cool the liquid by emitting and absorbing heat,respectively.
 2. The retrofit unit of claim 1, wherein the connectingelement comprises at least one passage for fluidly connecting theretrofit unit to the recipient and allowing said liquid to flow insidesaid cavity of the housing.
 3. The retrofit unit of claim 2, wherein theat least one passage comprises: an inlet passage for liquid entering theretrofit unit; and an outlet passage for liquid exiting the retrofitunit.
 4. The retrofit unit of claim 3, wherein the inlet passage isconnectable to a city water supply.
 5. The retrofit unit of claim 3,wherein the outlet passage is connectable to a drain of the recipient.6. The retrofit unit of claim 2, further comprising a hot/cold plateinside said cavity on the heat radiation side of the thermoelectricmodule, for circulating the liquid from the recipient inside the cavity.7. The retrofit unit of claim 6, further comprising a pump inside thecavity to circulate the liquid in the hot/cold plate.
 8. The retrofitunit of claim 2, further comprising a pump inside the cavity tocirculate the liquid between the cavity and the recipient.
 9. Theretrofit unit of claim 1, wherein said connecting element comprises atleast one of straps, thermally conductive adhesives, and thermallyconductive epoxy compounds to securely attach the retrofit unit to saidrecipient and thereby provide a physical contact between said housingand said recipient and a thermal contact between said thermoelectricdevice and said liquid in said recipient.
 10. The retrofit unit of claim1, wherein the thermoelectric device comprises a heat sink attached tothe at least one thermoelectric module.
 11. The retrofit unit of claim10, wherein the heat sink is attached to the heat radiation side of theat least one thermoelectric module.
 12. The retrofit unit of claim 10,wherein the heat sink is attached to the heat absorption side of the atleast one thermoelectric module to maintain the temperature of the heatabsorbing side close to an ambient temperature.
 13. The retrofit unit ofclaim 1, wherein the thermoelectric device comprises a hot/cold platehaving an embedded piping, the hot/cold plate attached to the heatabsorption side of the at least one thermoelectric module to maintainthe temperature of the heat absorbing side at an ambient temperature,the piping connected to a radiator to circulate a liquid coolant betweenthe radiator and the hot/cold plate.
 14. The retrofit unit of claim 1,wherein the thermoelectric device comprises at least one conductive heattransferring block attached to the at least one thermoelectric module.15. The retrofit unit of claim 12, wherein the thermoelectric devicecomprises a fan adjacent to said heat sink.
 16. The retrofit unit ofclaim 15, wherein the fan comprises an inlet duct positioned forretrieving ambient air.
 17. The retrofit unit of claim 13, wherein thethermoelectric device comprises a fan adjacent to said radiator.
 18. Theretrofit unit of claim 1, further comprising at least one thermometer insaid cavity for providing temperature readings to the control unit. 19.The retrofit unit of claim 18, wherein the control unit is adapted torecord and monitor the temperature readings to determine energy to beapplied to the at least one thermoelectric module.
 20. The retrofit unitof claim 1, wherein said control unit is adapted to determine powerenergy to be supplied from a power supply to the thermoelectric moduleduring peak and off-peak periods.
 21. The retrofit unit of claim 1,wherein said control unit is adapted to operate the thermoelectricmodule at a predetermined power in order to selectively heat and coolthe liquid, in a predetermined period of time.